The present invention generally relates to a firing cap arrangement for igniters and, more particularly, to a water-tight firing cap arrangement and method of making the same.
The igniters for fuses and delay fuses are wellknown in a variety of types. Many of these are so constructed that a user pulls a cord or pin, thereby releasing a firing mechanism which causes a firing pin to forcefully impact against a firing cap. This firing cap detonates, to thereby produce a flame or fire jet which sets fire to the fuse or delay fuse.
Many of these devices have a very complex internal mechanism which makes them not only expensive to produce but also contributes to the possibility of malfunction. More importantly, however, all of these igniters of the prior art have the disadvantage that the capacity for ignition exists only for a limited time, which is essentially the result of the composition of the material of the percussion charge of the firing cap, i.e. the chemical composition of the charge. It is known, for example, to provide firing caps which operate very well but which have a life of only approximately three years, due to the fact that the constituents of the chemical powder composition of the percussion charge are subjected to adverse climatic conditions. It is well known that prolonged and direct exposure to conditions of high moisture, for example due to rain, dew, snow or the like, adversely influences the detonating ability of the charge.
In order to counteract such environmental influences, the firing caps of the prior art are provided with foils and/or adhesive strips at the side at which the fire jet is produced. Such firing caps are also provided with a cover paper for covering a side of the percussion charge.
However, such prior art constructions are disadvantageous because they can only be used with relatively low weight powder and, when such powder is covered by paper, the paper easily detaches therefrom when exposed to water. The attachment and sealing of the foil paper at the flame side of the firing cap is a rather difficult as well as expensive operation which has not proven altogether satisfactory, particularly for military applications.